Note that since T-NeRF implicitly handles deformation, it is difficult to compute correspondences over time.
NSFF [1]} augments T-NeRF's implicit function \(F_t\)  to output an explicit scene flow field \(W_{t \rightarrow t+\delta }\)  between adjacent time steps \(t\)  and \(t+\delta \) ,
\(W_{t \rightarrow t+\delta }: \mathbf {x}\mapsto \mathbf {x}^\prime , \ \ \delta \in \lbrace +1, -1\rbrace .\) 
